I was a BM hunter back in wrath, which was considered unplayable in PvE for those that don't remember. Your pet scaled exceptionally well with flat AP, more so than agility, so I gemmed everything with the +40 AP gem. I was never top DPS but could generally keep up and even pass certain classes... playing an "unplayable" spec with bizarre items and gem choices.
The cool thing was that it worked. I was able to keep up with others playing a very unconventional build. And that's what an RPG should be about imo. Playing what you want, finding ways to make it work. Having the OPTIONS to try and make it work. Not being locked into anything. Current wow is nothing like this.